"Michael had severe bleeding and swelling to his brain. He had been complaining of headaches for the last few weeks but we put it down to migraines with the stress of his fight.

"It has been the longest 24 hours of our lives. My baby has lost his daddy. But he will be so so proud of his dad in what he achieved."

Towell's family were at the boxer's bedside in his final hours and are understood to have been joined by his manager, Tommy Gilmour.

Ms Ross said: "Once he was taken off of his life support He managed 12 hours, 12 whole rounds off his life support, he fought right to the end and he's done us all so proud...He left doing the thing he's best at...there's only one."

The couple had been together for more than eight years and had a young son, Rocco.

Towell's management are expected to release a statement on Saturday morning.

The British Boxing Board of Control, the sport's governing body and licensing authority, is yet to comment.

As news of the tragedy emerged members of the boxing community paid tribute to the sportsman, known as "Iron Mike Towell".

St Andrews Sporting Club said he "will always be in our hearts".

Trainer Shane McGuigan said on Twitter: "Heartbreaking news that Mike Towell has lost his life. May he rest in peace, thoughts go out to his loved ones. #RIP"

Promoter Eddie Hearn said: "Absolutely devastated by the passing of Mike Towell - all of our thoughts with his friends and family at this time."

Evans is yet to comment on his opponent's death, but described Towell as a "true warrior" in a statement issued after he was taken to hospital.

He said: "The ingredients were there for an entertaining fight and it was that, we are both punchers and so sadly for Mike he came out the wrong side.

"I never wanted to see my opponent being stretchered out of the ring. Who would ever want that sight? That was so hard for his family and my heart goes out to them."

The event at the Radisson Blu Hotel, Glasgow, was being broadcast on STV Glasgow when the Towell was fatally injured.

The boxer had been undefeated going into Thursday's fight, with 11 previous wins and one draw on his professional record, and the bout was an eliminator for the British welterweight title.

According to the BoxRec database of professional fights, Towell was knocked down in the first round and again in the fifth prior to the stoppage.

The bout was refereed by Victor Loughlin, who was also in charge of the British middleweight title fight in March between Chris Eubank and Nick Blackwell, which ended the latter's career after he suffered a bleed on the skull when he was stopped in 10 rounds.